Method of imaging localized infections

Abstract

The invention relates to a method for targeting an imaging agent to cells of an animal to detect localized infections. More particularly, localized infections are detected by targeting imaging agents to inflammatory cells having receptors for a vitamin by using vitamin-imaging agent conjugates.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]This application claims the benefit of priority under 35 U.S.C. §119(e) of U.S. provisional patent application Ser. No. 60 / 931,753 filed May 25, 2007, the disclosure of which is incorporated herein by reference in its entirety.FIELD OF THE INVENTION[0002]The invention relates to a method for targeting an imaging agent to cells of an animal to detect localized infections. More particularly, localized infections are detected by targeting imaging agents to inflammatory cells having receptors for a ligand, such as by using vitamin-imaging agent conjugates.BACKGROUND AND SUMMARY OF THE INVENTION[0003]Traditional methods for diagnosing infectious diseases rely on microscopic visualization of pathogens in a patient body fluid or tissue sample or the growth of the microorganism in the laboratory with the subsequent identification of the microorganism using clinical diagnostic tests. These techniques are generally reliable but are often time-consum...

AI Technical Summary

Benefits of technology

[0004]An inflammatory response is one of the first responses to infection. Inflammation results in increased blood flow to the area of infection, release of chemicals (e.g., chemoattractants) to attract leukocytes to the site of infection, and migration of immune cells, such as monocytes and macrophages, to the site of infection as a defense against the invading microorganisms. Inflammation can be initiated by production of eicosanoids and cytokines, which are released by injured or infected cells. Eicosanoids include prostoglandins which promote fever and dilate blood vessels during an inflammatory response, and leukotrienes which attract certain leukocytes to the site of infection, including monocytes and macrophages.

[0005]Monocytes and macrophages are vital to the regulation of immune responses and to the development of an inflammatory response. As part of the innate immune system, macrophages and monocytes are continuously monitoring the tissues in which they are located and thus play a major role when bacteria are encountered. Specifically, macrophages have the ability to recognize pathogen-associated molecular patterns through their surface receptors (e.g. toll-like receptors) and help orchestrate the secretion of pro-inflammatory cytokines and other mediators, as well as engage in the direct phagocytosis of the invading microorganism. Common cytokines that are involved in inflammation include interlerkins responsible for communication between white blood cells, and chemokines that promote chemotaxis during an inflammatory response. Cytokines both recruit immune cells to the site of infection and cause immune cell activation during an inflammatory response.

[0006]Folate receptors are expressed on a subset of macrophages (i.e., activated macrophages), and on monocytes. Monocytes and macrophages participate in the immune response by nonspecifically engulfing and killing foreign pathogens, by displaying degraded peptides from foreign proteins on their cell surfaces where they can be recognized by other immune cells, and by secreting cytokines and other factors that modulate the function of T and B lymphocytes, resulting in further stimulation of immune responses.

Problems solved by technology

These techniques are generally reliable but are often time-consuming.

Additionally, conventional methods of diagnosis, such as physical examinations, X-ray, CT scans, and ultrasonography, often fail to identify the location and / or the extent of infection in sites of localized infection (e.g., an abscess).

If left untreated, infections can damage host tissue, or can become chronic.

Infections can also become gangrenous, resulting in loss of an infected limb, or even death.

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